Diverse Polysaccharides Research Articles

Glucomannan engineering highlights roles of galactosyl modification in fine-tuning cellulose-glucomannan interaction in Arabidopsis cell walls

Widely found in most plant lineages, β-mannans are structurally diverse polysaccharides that can bind to cellulose fibrils to form the complex polysaccharide architecture of the cell wall. How changes in polysaccharide structure influence its cell wall solubility or promote appropriate interaction with cellulose fibrils is poorly understood. Glucomannan backbones acquire variable patterns of galactosyl substitutions, depending on plant developmental stage and species. Here, we show that fine-tuning of galactosyl modification on glucomannans is achieved by the differing acceptor recognition of mannan α-galactosyltransferases (MAGTs). Biochemical analysis and 13C solid-state nuclear magnetic resonance spectroscopy of Arabidopsis with cell wall glucomannan engineered by MAGTs reveal that the degree of galactosylation strongly affects the interaction with cellulose. The findings indicate that plants tailor galactosyl modification on glucomannans for constructing an appropriate cell wall architecture, paving the way to convert properties of lignocellulosic biomass for better use.

Discovery of two novel Flavobacterium species with potential for complex polysaccharide degradation

Polysaccharides are recognized for their extensive biological functions, holding significant promise for applications in both medicine and food industries. However, their utilization is frequently constrained by challenges such as high molecular weights and indistinct sugar chain structures. Recently, two novel bacterial strains, N6T and J3T, were isolated from the Nakdong River in Korea. These strains, which belong to the phylum Bacteroidota, are Gram-stain-negative, non-motile, aerobic, rod-shaped bacteria and have shown polysaccharide-degrading capabilities. Through comprehensive analyses, including 16S rRNA gene sequencing, whole-genome sequencing, and detailed morphological, physiological, and chemotaxonomic characterizations, these strains have been identified as new species within the genus Flavobacterium. KEGG pathway analysis further confirmed their robust capabilities for carbohydrate utilization. Additional investigations using the dbCAN and dbCAN-PUL databases identified the presence of carbohydrate-hydrolyzing enzymes (CAZymes) and polysaccharide utilization loci (PULs) within these strains, suggesting their potential to degrade various polysaccharides. Subsequent in vitro growth experiments demonstrated that strains N6T and J3T can degrade chitin, β-glucan, κ-carrageenan, and cellulose. Given their diverse polysaccharide degradation abilities, these strains are formally proposed to be named Flavobacterium polysaccharolyticum sp. nov. and Flavobacterium aureirubrum sp. nov. The type strains are designated as N6T (= KCTC 102173T = GDMCC 1.4609T) and J3T (= KCTC 102172T = GDMCC 1.4608T), respectively.

Selective utilization of medicinal polysaccharides by human gut Bacteroides and Parabacteroides species

Human gut Bacteroides and Parabacteroides species play crucial roles in human health and are known for their capacity to utilize diverse polysaccharides. Understanding how these bacteria utilize medicinal polysaccharides is foundational for developing polysaccharides-based prebiotics and drugs. Here, we systematically mapped the utilization profiles of 20 different medicinal polysaccharides by 28 human gut Bacteroides and Parabacteroides species. The growth profiles exhibited substantial variation across different bacterial species and medicinal polysaccharides. Ginseng polysaccharides promoted the growth of multiple Bacteroides and Parabacteroides species; in contrast, Dendrobium polysaccharides selectively promoted the growth of Bacteroides uniformis. This distinct utilization profile was associated with genomic variation in carbohydrate-active enzymes, rather than monosaccharides composition variation among medicinal polysaccharides. Through comparative transcriptomics and genetical manipulation, we validated that the polysaccharide utilization locus PUL34_Bu enabled Bacteroides uniformis to utilize Dendrobium polysaccharides (i.e. glucomannan). In addition, we found that the GH26 enzyme in PUL34_Bu allowed Bacteroides uniformis to utilize multiple plant-derived mannan. Overall, our results revealed the selective utilization of medicinal polysaccharide by Bacteroides and Parabacteroides species and provided insights into the use of polysaccharides in engineering the human gut microbiome.

Heterogeneity in Mechanical Properties of Plant Cell Walls.

The acquisition and utilization of cell walls have fundamentally shaped the plant lifestyle. While the walls provide mechanical strength and enable plants to grow and occupy a three-dimensional space, successful sessile life also requires the walls to undergo dynamic modifications to accommodate size and shape changes accurately. Plant cell walls exhibit substantial mechanical heterogeneity due to the diverse polysaccharide composition and different development stages. Here, we review recent research advances, both methodological and experimental, that shed new light on the architecture of cell walls, with a focus on the mechanical heterogeneity of plant cell walls. Facilitated by advanced techniques and tools, especially atomic force microscopy (AFM), research efforts over the last decade have contributed to impressive progress in our understanding of how mechanical properties are associated with cell growth. In particular, the pivotal importance of pectin, the most complex wall polysaccharide, in wall mechanics is rapidly emerging. Pectin is regarded as an important determinant for establishing anisotropic growth patterns of elongating cells. Altogether, the diversity of plant cell walls can lead to heterogeneity in the mechanical properties, which will help to reveal how mechanical factors regulate plant cell growth and organ morphogenesis.

Diverse polysaccharide production and biofilm formation abilities of clinical Klebsiella pneumoniae

Klebsiella pneumoniae infections have become a growing threat for human health. The lack of understanding of the relationship between antibiotic resistance, mucoviscosity, and biofilm formation impedes our abilities to effectively predict K. pneumoniae infection outcomes. The Multidrug-Resistant Organism Repository and Surveillance Network offers a unique opportunity into the genetic and phenotypic variabilities in the K. pneumoniae isolates. To this end, we compared the genetic profiles of these isolates with the phenotypic biofilm formation, percent mucoviscosity, and growth rates. There was a significant phenotype-genotype correlation with decreased biofilm formation and an insertion sequence in the transcriptional activator of the type III fimbrial system. Interestingly, the most mucoid strains in the populations were lacking the genetic element regulating the mucoid phenotype and three of these isolates were able to form robust biofilms. The combination of phenotypic, genomic, and image analyses revealed an intricate relation between growth, mucoviscosity and specific virulence-associated genetic determinants.

Polysaccharide-induced colloidal stabilization of red wines: Impact on phenolic composition and color characteristic

Polysaccharides play a crucial role in wine quality and colloidal stability. Two types of polysaccharides were applied to three wines with diverse initial phenolic and polysaccharide profiles to evaluate their effects on the color characteristics of the wines. Changes in the colloidal properties, phenolic composition, and color parameters of the wines were analyzed over a one-year bottle aging. The results revealed that the addition of polysaccharides consisting mainly of arabinogalactans (AG) tended to have a higher absolute zeta (ζ) potential value (below −10 mV), indicative of enhanced colloidal stability, while mannoprotein (MP) had little effect. However, the addition of both polysaccharides can influence the colloidal particle size and turbidity of the wines, with distinct variations observed based on the initial matrix composition, especially the polysaccharide content. Furthermore, both polysaccharides promoted the formation and accumulation of anthocyanin derivatives, especially pyranoanthocyanin, while AG had a greater effect, with a maximum increase of nearly 14% compared with the control group at 12 M. The color characteristic of the wines changed accordingly, with a significant increase in the red hue (a∗ value), particularly in wines characterized by low polysaccharide content and high polyphenol level. Notably, the modifications in colloidal properties induced by polysaccharide displayed a significant correlation with polyphenols and color parameters, indicating that a stable colloidal system facilitates color stability. In practical winemaking applications, the addition of polysaccharides should consider factors such as their type, concentration, and the balance of the initial wine composition.

Extraction, purification, characterization and antidiabetic mechanisms of plant polysaccharides: a critical review

Abstract Diabetes mellitus (DM) represents a heterogeneous and multifactorial metabolic disorder, leading to diverse economic challenges and health complications, significantly affecting individuals’ lives. Type 2 diabetes (T2DM) stands as the predominant form of diabetes, with its onset influenced by a range of genetic and environmental factors. Currently, conventional diabetic medications are employed in clinical practice, but they may entail certain side effects. Fortunately, diverse natural polysaccharides extracted from plants exhibit antidiabetic properties, which have been demonstrated to effectively mitigate hyperglycemia, reverse insulin resistance, and forestall complications associated with diabetes. Consequently, exploring the utilization of these polysaccharides as adjuncts to conventional therapies has emerged as a novel research direction in recent years. Thus, this review centers on the extraction, purification, and characterization of plant polysaccharides, providing an overview of the advancements in the antidiabetic effects and mechanisms of natural polysaccharides. This perspective offers fresh insights to explore potential research domains and enhances understanding for the development of diabetic drugs derived from polysaccharides.

Diverse polysaccharide production and biofilm formation abilities of clinical Klebsiella pneumoniae.

Klebsiella pneumoniae infections have become a growing threat for human health. The lack of understanding of the relationship between antibiotic resistance, mucoviscosity, and biofilm formation in clinical isolates impedes our abilities to effectively predict K. pneumoniae infection outcomes. These traits are also associated with fitness in natural populations and more specifically within a host. The Multidrug-Resistant Organism Repository and Surveillance Network offers a unique opportunity into the genetic and phenotypic variabilities in the K. pneumoniae isolates encountered in the clinics today. To this end, we compared the genetic profiles of these isolates with the phenotypic biofilm formation abilities, percent mucoviscosity, and growth rates. We found most isolates formed limited biofilm, although a select group of isolates could form extremely robust biofilms. Variation in biofilm formation could not be explained by difference in growth rate, suggesting specific genetic and physical determinants. Interestingly, the most mucoid strains in the populations were lacking the genetic element regulating the mucoid phenotype and three of these isolates were able to form robust biofilms. There was a significant phenotype-genotype correlation with decreased biofilm formation and an insertion sequence in the transcriptional activator of the type III fimbrial system. Finally, confocal microscopy highlighted the structural and spatial heterogeneity of biofilm among the most robust biofilm formers not detected by traditional methods. The combination of phenotypic, genomic and image analyses allowed us to reveal an unexpected phenotypic diversity and an intricate relation between growth, mucoviscosity and specific virulence-associated genetic determinants.

Synthesis of a Phosphoethanolamine Cellulose Mimetic and Evaluation of Its Unanticipated Biofilm Modulating Properties.

When coordinating and adhering to a surface, microorganisms produce a biofilm matrix consisting of extracellular DNA, lipids, proteins, and polysaccharides that are intrinsic to the survival of bacterial communities. Indeed, bacteria produce a variety of structurally diverse polysaccharides that play integral roles in the emergence and maintenance of biofilms by providing structural rigidity, adhesion, and protection from environmental stressors. While the roles that polysaccharides play in biofilm dynamics have been described for several bacterial species, the difficulty in isolating homogeneous material has resulted in few structures being elucidated. Recently, Cegelski and co-workers discovered that uropathogenic Escherichia coli (UPEC) secrete a chemically modified cellulose called phosphoethanolamine cellulose (pEtN cellulose) that plays a vital role in biofilm assembly. However, limited chemical tools exist to further examine the functional role of this polysaccharide across bacterial species. To address this critical need, we hypothesized that we could design and synthesize an unnatural glycopolymer to mimic the structure of pEtN cellulose. Herein, we describe the synthesis and evaluation of a pEtN cellulose glycomimetic which was generated using ring-opening metathesis polymerization. Surprisingly, the synthetic polymers behave counter to native pEtN cellulose in that the synthetic polymers repress biofilm formation in E. coli laboratory strain 11775T and UPEC strain 700415 with longer glycopolymers displaying greater repression. To evaluate the mechanism of action, changes in biofilm and cell morphology were visualized using high resolution field-emission gun scanning electron microscopy which further revealed changes in cell surface appendages. Our results suggest synthetic pEtN cellulose glycopolymers act as an antiadhesive and inhibit biofilm formation across E. coli strains, highlighting a potential new inroad to the development of bioinspired, biofilm-modulating materials.

Determining glycosyltransferase functional order via lethality due to accumulated O-antigen intermediates, exemplified with Shigella flexneri O-antigen biosynthesis.

The O antigen (OAg) polysaccharide is one of the most diverse surface molecules of Gram-negative bacterial pathogens. The structural classification of OAg, based on serological typing and sequence analysis, is important in epidemiology and the surveillance of outbreaks of bacterial infections. Despite the diverse chemical structures of OAg repeating units (RUs), the genetic basis of RU assembly remains poorly understood and represents a major limitation in assigning gene functions in polysaccharide biosynthesis. Here, we describe a genetic approach to interrogate the functional order of glycosyltransferases (GTs). Using Shigella flexneri as a model, we established an initial glycosyltransferase (IT)-controlled system, which allows functional order allocation of the subsequent GT in a 2-fold manner as follows: (i) first, by reporting the growth defects caused by the sequestration of UndP through disruption of late GTs and (ii) second, by comparing the molecular sizes of stalled OAg intermediates when each putative GT is disrupted. Using this approach, we demonstrate that for RfbF and RfbG, the GT involved in the assembly of S. flexneri backbone OAg RU, RfbG, is responsible for both the committed step of OAg synthesis and the third transferase for the second L-Rha. We also show that RfbF functions as the last GT to complete the S. flexneri OAg RU backbone. We propose that this simple and effective genetic approach can be also extended to define the functional order of enzymatic synthesis of other diverse polysaccharides produced both by Gram-negative and Gram-positive bacteria.IMPORTANCEThe genetic basis of enzymatic assembly of structurally diverse O antigen (OAg) repeating units (RUs) in Gram-negative pathogens is poorly understood, representing a major limitation in our understanding of gene functions for the synthesis of bacterial polysaccharides. We present a simple genetic approach to confidently assign glycosyltransferase (GT) functions and the order in which they act during assembly of the OAg RU. We employed this approach to determine the functional order of GTs involved in Shigella flexneri OAg assembly. This approach can be generally applied in interrogating GT functions encoded by other bacterial polysaccharides to advance our understanding of diverse gene functions in the biosynthesis of polysaccharides, key knowledge in advancing biosynthetic polysaccharide production.

Lytic Capsule-Specific Acinetobacter Bacteriophages Encoding Polysaccharide-Degrading Enzymes

The genus Acinetobacter comprises both environmental and clinically relevant species associated with hospital-acquired infections. Among them, Acinetobacter baumannii is a critical priority bacterial pathogen, for which the research and development of new strategies for antimicrobial treatment are urgently needed. Acinetobacter spp. produce a variety of structurally diverse capsular polysaccharides (CPSs), which surround the bacterial cells with a thick protective layer. These surface structures are primary receptors for capsule-specific bacteriophages, that is, phages carrying tailspikes with CPS-depolymerizing/modifying activities. Phage tailspike proteins (TSPs) exhibit hydrolase, lyase, or esterase activities toward the corresponding CPSs of a certain structure. In this study, the data on all lytic capsule-specific phages infecting Acinetobacter spp. with genomes deposited in the NCBI GenBank database by January 2024 were summarized. Among the 149 identified TSPs encoded in the genomes of 143 phages, the capsular specificity (K specificity) of 46 proteins has been experimentally determined or predicted previously. The specificity of 63 TSPs toward CPSs, produced by various Acinetobacter K types, was predicted in this study using a bioinformatic analysis. A comprehensive phylogenetic analysis confirmed the prediction and revealed the possibility of the genetic exchange of gene regions corresponding to the CPS-recognizing/degrading parts of different TSPs between morphologically and taxonomically distant groups of capsule-specific Acinetobacter phages.

Biochemical characterization of Fsa16295Glu from "Fervidibacter sacchari," the first hyperthermophilic GH50 with β-1,3-endoglucanase activity and founding member of the subfamily GH50_3.

The aerobic hyperthermophile "Fervidibacter sacchari" catabolizes diverse polysaccharides and is the only cultivated member of the class "Fervidibacteria" within the phylum Armatimonadota. It encodes 117 putative glycoside hydrolases (GHs), including two from GH family 50 (GH50). In this study, we expressed, purified, and functionally characterized one of these GH50 enzymes, Fsa16295Glu. We show that Fsa16295Glu is a β-1,3-endoglucanase with optimal activity on carboxymethyl curdlan (CM-curdlan) and only weak agarase activity, despite most GH50 enzymes being described as β-agarases. The purified enzyme has a wide temperature range of 4-95°C (optimal 80°C), making it the first characterized hyperthermophilic representative of GH50. The enzyme is also active at a broad pH range of at least 5.5-11 (optimal 6.5-10). Fsa16295Glu possesses a relatively high kcat/KM of 1.82 × 107 s-1 M-1 with CM-curdlan and degrades CM-curdlan nearly completely to sugar monomers, indicating preferential hydrolysis of glucans containing β-1,3 linkages. Finally, a phylogenetic analysis of Fsa16295Glu and all other GH50 enzymes revealed that Fsa16295Glu is distant from other characterized enzymes but phylogenetically related to enzymes from thermophilic archaea that were likely acquired horizontally from "Fervidibacteria." Given its functional and phylogenetic novelty, we propose that Fsa16295Glu represents a new enzyme subfamily, GH50_3.

New Vision of Cell Walls in Aspergillus fumigatus from Solid-State NMR Spectroscopy.

The fungal cell wall plays a critical role in regulating cellular integrity and communication, and serves as a frontline defense against stress. It is also a prime target for the development of antifungal agents. The cell wall is comprised of diverse polysaccharides and proteins and poses a challenging target for high-resolution structural characterization. Recently, the solid-state nuclear magnetic resonance (ssNMR) analysis of intact Aspergillus fumigatus cells has provided atomic-level insights into the structural polymorphism and functional assembly principles of carbohydrate components within the cell wall. This physical perspective, alongside structural information from biochemical assays, offers a renewed understanding of the cell wall as a highly complex and dynamic organelle. Here, we summarize key conceptual advancements in the structural elucidation of A. fumigatus mycelial and conidial cell walls and their responses to stressors. We also highlight underexplored areas and discuss the opportunities facilitated by technical advancements in ssNMR spectroscopy.

Exploring the Therapeutic Potential: Phytochemistry and Pharmacology of Bryophyllum pinnatum

Bryophyllum pinnatum, a renowned medicinal plant with a rich history in various traditional medical practices, has been utilized for treating a range of ailments such as fever, smallpox, otitis, cough, asthma, headache, convulsion, and general debility. The plant's diverse secondary metabolites, including steroids, flavonoids, terpenoids, fatty acids, bufadienolides, proteins, peptides, vitamins, and polysaccharides, have been identified. Over the past thirty years, extensive research has unveiled the plant's pharmacological effects both in vivo and in vitro, demonstrating its antimicrobial, anti-ulcer, antihypertensive, antileishmanial, anti-cancer, antidiabetic, and immunomodulatory properties.
 This comprehensive review aims to provide a consolidated overview of Bryophyllum pinnatum, encompassing its traditional uses, phytochemistry, and pharmacological studies. By presenting a wealth of information, this paper seeks to inspire further exploration into the potential beneficial applications of the plant. Additionally, it sheds light on the clinical uses and prospects of Bryophyllum pinnatum, offering valuable insights for future research endeavors.
 Keywords: Bryophyllum pinnatum, Chemical Constituent, Biological activities, antioxidant effect, Therapeutic potential

Pontiella agarivorans sp. nov., a novel marine anaerobic bacterium capable of degrading macroalgal polysaccharides and fixing nitrogen.

Marine macroalgae produce abundant and diverse polysaccharides, which contribute substantially to the organic matter exported to the deep ocean. Microbial degradation of these polysaccharides plays an important role in the turnover of macroalgal biomass. Various members of the Planctomycetes-Verrucomicrobia-Chlamydia (PVC) superphylum are degraders of polysaccharides in widespread anoxic environments. In this study, we isolated a novel anaerobic bacterial strain NLcol2T from microbial mats on the surface of marine sediments offshore Santa Barbara, CA, USA. Based on 16S ribosomal RNA (rRNA) gene and phylogenomic analyses, strain NLcol2T represents a novel species within the Pontiella genus in the Kiritimatiellota phylum (within the PVC superphylum). Strain NLcol2T is able to utilize various monosaccharides, disaccharides, and macroalgal polysaccharides such as agar and ɩ-carrageenan. A near-complete genome also revealed an extensive metabolic capacity for anaerobic degradation of sulfated polysaccharides, as evidenced by 202 carbohydrate-active enzymes (CAZymes) and 165 sulfatases. Additionally, its ability of nitrogen fixation was confirmed by nitrogenase activity detected during growth on nitrogen-free medium, and the presence of nitrogenases (nifDKH) encoded in the genome. Based on the physiological and genomic analyses, this strain represents a new species of bacteria that may play an important role in the degradation of macroalgal polysaccharides and with relevance to the biogeochemical cycling of carbon, sulfur, and nitrogen in marine environments. Strain NLcol2T (= DSM 113125T = MCCC 1K08672T) is proposed to be the type strain of a novel species in the Pontiella genus, and the name Pontiella agarivorans sp. nov. is proposed.IMPORTANCEGrowth and intentional burial of marine macroalgae is being considered as a carbon dioxide reduction strategy but elicits concerns as to the fate and impacts of this macroalgal carbon in the ocean. Diverse heterotrophic microbial communities in the ocean specialize in these complex polymers such as carrageenan and fucoidan, for example, members of the Kiritimatiellota phylum. However, only four type strains within the phylum have been cultivated and characterized to date, and there is limited knowledge about the metabolic capabilities and functional roles of related organisms in the environment. The new isolate strain NLcol2T expands the known substrate range of this phylum and further reveals the ability to fix nitrogen during anaerobic growth on macroalgal polysaccharides, thereby informing the issue of macroalgal carbon disposal.

A review on phytochemical screening and pharmacological activities of fruit of Indian mallow

a native traditional plant commonly known as Indian Mallow, is a versatile plant species that brings enormous amounts of medicinal uses from the history of traditional culture. This review emphasizes the current body of knowledge surrounding the effects of , highlighting its potential therapeutic application. The plant is well renowned for its diverse phytochemical composition, including alkaloids, flavonoids, and polysaccharides, which contribute to its wide-ranging biological activity. It has been discovered through research that Abutilon indicum extracts possess noteworthy pharmacological effects, including anti-oxidant, anti-inflammatory, anti-microbial, anti-diabetic, and hepatoprotective properties. In addition to its immunomodulatory effects, larvicidal, anti-convulsant, neuroprotective, and cognitive-enhancing capacities have gained attention in recent years and serve as natural alternatives to available allopathic medicine.The focus of the review revolves around various noteworthy pharmacological effects of , including its anti-inflammatory, anti-microbial, anti-oxidant, and anti-convulsant properties. Furthermore, the examination of the plant extracts' phytochemical composition is also emphasized.Those activities were discussed and reported with standard methods and compared with the available standard drugs. Overall, this comprehensive review provides valuable insights into the pharmacological effects of , underscoring its potential as a source of novel therapeutic agents and paving the way for future research and development.

Impact of structurally diverse polysaccharides on colonic mucin O-glycosylation and gut microbiota

Understanding how dietary polysaccharides affect mucin O-glycosylation and gut microbiota could provide various nutrition-based treatments. Here, the O-glycan profile of the colonic mucosa and gut microbiome were investigated in C57BL/6J mice fed six structurally diverse dietary polysaccharides and a mixture of six fibers. Dietary polysaccharides increased total O-glycans, mainly by stimulating neutral glycans. Highly branched arabinogalactan promoted terminally fucosylated core 1 O-glycans; whereas linear polysaccharides, including pectin, konjac glucomannan, inulin, and the fiber mixture, favored terminally di-fucosylated O-glycans. The last three polysaccharides also lowered the level of sulfated O-glycans and sialylated mono-fucosylated O-glycans. Varied monosaccharide composition in mixed polysaccharides had a synergistic beneficial effect, boosting fucosylated neutral glycans, decreasing acidic glycans, and stimulating microbial richness and diversity. Dietary polysaccharides containing arabinose and sulfate groups enhanced the relative abundances of Akkermansia and Muribaculaceae, respectively. The present comparison reveals the relationship between dietary polysaccharide structure, mucin O-glycan composition, and intestinal microorganisms.

Synthesis and characterization of stimuli responsive micelles from chitosan, starch, and alginate based on graft copolymers with polylactide-poly(methacrylic acid) and polylactide- poly[2(dimethyl amino)ethyl methacrylate] side chains

The primary objective of this paper is to serve as a comprehensive study on the synthesis of stimulus-sensitive micelles based on polysaccharides. In pursuit of this goal, functionalization with polylactide (PLA) was used as the water-resistance part and poly[2(Dimethyl amino)ethyl methacrylate] (PDMAEMA) or poly(methacrylic acid) (PMA) were employed as the stimulus-sensitive part to create micelles with a simple structure. FTIR and 1HNMR measurements were utilized to characterize the functionalized polysaccharides. Fluorescence spectroscopy was used to determine the critical micelle concentration. The average micelles' diameter, as observed in SEM and TEM pictures, ranges from 50 to 200 nm. To gain a better understanding of the potential of theses micelles for delivering drugs in a stimulus-sensitive manner, drug release tests were conducted. The cytotoxicity of these nano-vehicles was examined using the MTT assay. Utilizing MCF7 cells stained with DAPI and Mito Tracker, cellular uptake studies were also investigated. The results indicate that the behavior of the micelles is nearly same even though they used polysaccharides with various charge densities or different stimulus sensitive polymers. This approach, therefore, demonstrates that a broad range of micelle production is possible by employing diverse polysaccharides functionalized with PLA and polymethacrylates.

Investigation of the structural and immunomodulatory properties of alkali-soluble β-glucans from Pleurotus eryngii fruiting bodies

Fungal β-glucans have received a lot of interest due to their proinflammatory activity towards cells of the innate immune system. Although commonly described as (1➔3)-β-glucans with varying degree of (1➔6)-branching, the fungal β-glucans constitute a diverse polysaccharide class. In this study, the alkali-soluble β-glucans from the edible mushroom Pleurotus eryngii were extracted and characterized by GC, GC–MS and 2D NMR analyses. The extracts contain several structurally different polysaccharides, including a (1➔3)-β-d-glucan with single glucose units attached at O-6, and a (1➔6)-β-d-glucan, possibly branched at O-3. The immunomodulatory activities of the P. eryngii extracts were assessed by investigating their ability to bind to the receptor dectin-1, and their ability to induce production of the proinflammatory cytokines TNF-α, IL-6 and IL-1β in LPS-differentiated THP-1 cells. Although the samples were able to bind to the dectin-1a receptor, they did not induce production of significant levels of cytokines in the THP-1 cells. Positive controls of yeast-derived (1➔3)-β-d-glucans with branches at O-6 induced cytokine production in the cells. Thus, it appears that the P. eryngii β-glucans are unable to induce production of proinflammatory cytokines in LPS-differentiated THP-1 cells, despite being able to activate the human dectin-1a receptor.

Functional characterization of fungal lytic polysaccharide monooxygenases for cellulose surface oxidation

BackgroundMicrobial lytic polysaccharide monooxygenases (LPMOs) cleave diverse biomass polysaccharides, including cellulose and hemicelluloses, by initial oxidation at C1 or C4 of glycan chains. Within the Carbohydrate-Active Enzymes (CAZy) classification, Auxiliary Activity Family 9 (AA9) comprises the first and largest group of fungal LPMOs, which are often also found in tandem with non-catalytic carbohydrate-binding modules (CBMs). LPMOs originally attracted attention for their ability to potentiate complete biomass deconstruction to monosaccharides. More recently, LPMOs have been applied for selective surface modification of insoluble cellulose and chitin.ResultsTo further explore the catalytic diversity of AA9 LPMOs, over 17,000 sequences were extracted from public databases, filtered, and used to construct a sequence similarity network (SSN) comprising 33 phylogenetically supported clusters. From these, 32 targets were produced successfully in the industrial filamentous fungus Aspergillus niger, 25 of which produced detectable LPMO activity. Detailed biochemical characterization of the eight most highly produced targets revealed individual C1, C4, and mixed C1/C4 regiospecificities of cellulose surface oxidation, different redox co-substrate preferences, and CBM targeting effects. Specifically, the presence of a CBM correlated with increased formation of soluble oxidized products and a more localized pattern of surface oxidation, as indicated by carbonyl-specific fluorescent labeling. On the other hand, LPMOs without native CBMs were associated with minimal release of soluble products and comparatively dispersed oxidation pattern.ConclusionsThis work provides insight into the structural and functional diversity of LPMOs, and highlights the need for further detailed characterization of individual enzymes to identify those best suited for cellulose saccharification versus surface functionalization toward biomaterials applications.